Resets, recoveries and sign-ups lean on a phone number. These signals ask the carrier what the number can't tell you.
Before a password reset or MFA move, asks the carrier whether the SIM on the employee's number changed in the last 72 hours.
Tells you whether every call to the line, voice codes included, is being sent somewhere else.
Compares what a person says (name, birthdate, zip) with what their carrier holds, and returns match or no match per field. Nothing comes back but the answer.